Invasive blood pressure monitoring is frequently performed on critically infirmed patients in intensive care and critical care units and on patients undergoing critical surgeries. It is gaining widespread acceptance in the care and treatment of cardiac patients as a technique for constant, accurate determination of blood pressure in the heart. The most widely used technique for invasive blood pressure monitoring is catheterization. A catheter is inserted through a peripheral blood vessel into a patient's circulatory system with the distal end of the catheter opening into the blood stream. The catheter is threaded through the blood vessel until it is positioned at the desired location for measuring arterial or venous blood pressure and may be positioned in the right heart or pulmonary artery to measure atrial, ventricular or pulmonary artery pressures.
An IV set is generally attached to the proximal end of the catheter protruding from the patient. An IV solution bag and the IV set assembly contain a solution such as, for example, a sterile saline solution, which flows through the catheter into the patient. The IV solution provides a fluid pathway for monitoring pressure in the patient's circulatory system. By positioning a pressure transducer along the fluid pathway, the blood pressure in the patient's circulatory system can be monitored.
A typical pressure transducer for use in invasive blood pressure monitoring systems comprises a thin diaphragm which is capable of being deflected by the pressure pulses which travel through the fluid column in the catheter and tubing. Some type of mechanism is provided for measuring the deflection of the diaphragm, usually suitable electronic circuitry configured to generate an electrical signal representing the pressure exerted on the diaphragm.
Reusable and disposable pressure transducers are commercially available. Reusable pressure transducers often consist of a disposable dome which functions as a reservoir for the IV fluid. The dome includes a resilient diaphragm contiguous with the diaphragm of the pressure transducer. The pressure pulses are transmitted through the dome diaphragm to the transducer diaphragm. The transducer measures the deflection of the diaphragm and converts the pressure fluctuation into electrical impulses which are transmitted to a monitor. These pressure transducers can be reused following sterilization because the diaphragm of the transducer is not in direct contact with the fluid being administered. Only the disposable dome and diaphragm contact the fluid. An example of a reusable pressure transducer is disclosed and described in U.S. Pat. No. 4,610,256 entitled PRESSURE TRANSDUCER, issued Sept. 9, 1986 in the name of Wallace, the entire disclosure of which is incorporated herein by reference.
Disposable pressure transducers generally include a housing defining a flow-through chamber having an inlet and outlet port, and a pressure transducer mounted in a second chamber. The transducer is exposed to the first chamber but separated from the fluid in the first chamber by an insulating medium, such as silicone gel. Fluid pressure can be transmitted across the insulating medium, but electrical current cannot.
The transducer is generally a silicon chip a portion of which forms a thin diaphragm which deflects in response to pressure impulses in the fluid column. Electrical conductors in contact with circuitry on the silicon chip lead from the transducer and are encased in an insulated sheath to form a short length of electrical cable with an end connector (a "pigtail" or "adapter" cable). The adapter cable can in turn be connected to a longer extension cable leading to a monitor.
Examples of disposable pressure transducers are described and disclosed in U.S. Pat. No. 4,539,998 entitled PRESSURE TRANSDUCER ASSEMBLY, issued Sept. 10, 1985 in the name of McCord, U.S. Design Pat. No. 282,284 entitled TRANSDUCER HOUSING ASSEMBLY FOR MONITORING BLOOD PRESSURE AND THE LIKE, issued Jan. 21, 1986, in the name of McCord et al, and U.S. Pat. No. 4,576,18l entitled A DISPOSABLE PRESSURE TRANSDUCER APPARATUS FOR MEDICAL USE, issued Mar. 18, 1986 in the name of Wallace et al. the disclosures of which are incorporated herein by reference.
Typically, the pressure transducers have mounting brackets as shown on the transducers in FIG. 1 of U.S. Pat. No. 4,576,18l, FIG. 1 of U.S. Pat. No. 4,539,998, and FIG. 1 of U.S. Design Pat. No. 282,284. The brackets may have slots formed therein through which tape or straps may be positioned to secure the transducer to an IV pole, to the patient himself, or to a fluid manifold adjacent the patient's bedside.
Another example of a disposable pressure transducer is shown in U.S. Pat. No. 4,776,343 entitled DISPOSABLE PRESSURE TRANSDUCER FOR USE WITH A CATHETER, issued in the name of Hubbard et al. The housing of the Hubbard pressure transducer has a flange for horizontal or vertical mounting on a conventional pole clamp on an IV pole, and a splash curtain to protect the cable connection from fluid splash.
FIG. 1 herein shows a prior art medical device organizer mounted on an IV pole with transducers of the type disclosed in U.S. Pat. Nos. 4,576,18l and 4,539,998 attached. As shown in FIG. 1, the mounting brackets of transducer 1 (the type disclosed in the '181 patent) slide into the slots or grooves provided on the organizer by flanges 3, whereas the mounting brackets of transducer 5 (the type disclosed in the '998 patent) slide into the slots or grooves provided on the organizer by flanges 7.
Short lengths of electrical cable ("pigtail" or "adapter" cables) 9 and 11 extend from each transducer to electrical connectors 13 and 15, respectively. Electrical connectors 13 and 15 are in turn connected to electrical connectors 17 and 19 on electrical cables 21 and 23, respectively, which lead to a monitor. Port 14 formed in electrical connector 13 provides means for venting and calibrating the back side of pressure transducer 1 through an air passageway in adapter cable 9. Tubing 25 and 27 connect to an IV bag and tubing 29 and 31 connect to a catheter inserted into the patient.
The organizer shown in FIG. 1 is a convenient method of mounting several pressure transducers or other medical devices and accessories, such as, for example, flush devices, stopcocks, and tubing in a neat organized fashion on an IV pole at a patient's bedside. One of the disadvantages of the support plate shown in FIG. 1 is that in response to patient strain on lines 29 and 31, there is danger of breaking the connection between the tubing and the pressure transducer at stopcocks 2B and 30, respectively, which interrupts fluid flow to the patient and can pose a serious threat to the patient. Another disadvantage is that the organizer provides no electrical interconnection between the pressure transducer or other medical device and a monitor. Thus, it is necessary to provide an adapter cable as part of the transducer or medical device.
There is a need for a pole mounted organizer that neatly and conveniently holds a plurality of medical devices, but at the same time provides some strain relief if patient movement exerts too much force on the tubing connected to the medical device. There is also a need for an organizer that provides means for connecting a medical device to a monitor without incorporating an adapter cable into the medical device.